There are numerous industrial situations where it is desirable to have a nickel-base overlay deposed over a steel substrate. In particular, overlay applications include continuous casting rolls in steel mills, basic oxygen process ("BOP") furnace hood tubing, and centrifugal casting molds for tubing.
Other typical non-limiting applications involve low alloy steels that suffer repeated, severe temperature cycles causing them to fail by thermal fatigue cracking. For instance, it is desirable to overlay hot forging dies and extrusion dies where deformation by the work being done is not the overwhelming cause of failure.
Efforts have been undertaken wherein 606 and 625 alloys are used as overlays. However, it is desirable to have an overlay that is rich in nickel and lower in chromium so that the COE and TC are approximately equal to those of the underlay mild steel substrate after iron dilution has occurred.
Accordingly, there is a need for an overlay composition that closely matches the COE and TC of a steel substrate while simultaneously providing adequate protection.